This invention concerns a device to draw back a moving component, a switch incorporating such a device, and its use in magnetically operated relays. More specifically, it concerns a device to draw back a moving component which can adopt at least two different positions, an "on" position under the effect of an external force, and an "off" position, under the effect of a drawback force.
Such devices frequently consist of a component possessing elastic properties, and which is usually described as a spring. Such a spring may be a flat plate spring, or a coil spring. More specifically, monostable switches, with a stable position (the "off" position) and an unstable position (the "on" position), in which the switch is held by the effect of an external force (a magnetic field in the case of a relay) often comprise a metal blade or flat spring to return the switch to the stable position.
The spring used in such cases is usually formed of a material differing from that of the moving part, to which it is soldered or fixed in some other way. In the case of miniaturized relays, increasingly used in electronics, this flat spring is extremely small and therefore difficult to handle, and its position difficult to adjust accurately. The same difficulties arise in attaching the moving component, and in general in all operations involving such tiny springs.
Such springs are also quite expensive, being made from specific materials such as beryllium copper and further requiring special treatment to bestow them with adequate elasticity.
Finally, any mechanical spring is subject to aging, which alters its elastic properties after a certain lapse of time.
This new drawback device overcomes such disadvantages.
Further details on the operation of switches such as the one illustrated in FIG. 2 may be obtained from the article entitled "New construction for a mercury-wetted switch for operation in any position" by Legrand and Frances, published in Volume 2, pp. 625 to 634 of the "Proceedings of the Tenth International Conference on Electric Contact Phenomena", held in Budapest from 25th to 29th Aug. 1980.